U.S. Pat. No. 6,828,008 to Gruber discloses providing an edge coating of a superabsorbent polymer (“SAP”) on the tape to prevent paints and other liquids from wicking into the paper or fabric substrate for the tape or from bleeding between the tape substrate and the surface to which the tape is applied (the “adherend”).
SAPs have a strong affinity for water and appear to function in the Gruber tapes by absorbing water from water-based coatings, such as latex paints. This appears to increase the viscosity of the coating and thereby reduce its tendency to be absorbed into the tape backing or to pass between the adhesive and the adherend thereby.